Foreign-born individuals (e.g., legal immigrants and refugees with class B1 and B2 TB notification status),f including children who recently arrived (≤5 years) from countries with high incidence or prevalence of TB and those adopted from outside US144bef

Children <5 yearsf of age or infants, children, and adolescents exposed to adults in high-risk categories;121ef annual testing recommended in high-risk pediatric patients (e.g., individuals from countries with high prevalence of TB, low-income groups, children infected with HIV, incarcerated adolescents)be

History of BCG vaccination does not rule out use of tuberculin testing to aid diagnosis of TB infection.bc (See False-positive Reactions under Cautions.)

Tuberculin Dosage and Administration

General

Document test result in permanent medical record.c Include name of preparation, manufacturer and lot number, administration technique (i.e., Mantoux method), date and dose administered, date of test reading, and extent of induration in mm (including 0).c121 Recording result only as “negative” or “positive” is not adequate.c

Administration

Intradermal Administration

Administer by intradermal injection using Mantoux method.bc Avoid administering by IV, IM, or sub-Q.bc Sub-Q injection lacks diagnostic value and may result in adverse reactions (e.g., general febrile reaction, acute inflammation around old tuberculous lesions) in highly sensitive individuals.c

Use tuberculin syringe with short (0.25–0.5 inch) 26- or 27-gauge needle.bc Use a separate sterile, single-use disposable syringe and needle for each individual patient to prevent transmission of infectious agents (e.g., HIV, hepatitis virus).bc To avoid contamination of vial content (and subsequent transmission of infectious agents to other individuals), never use the same needle and/or syringe to re-enter multidose vial, even when used for the same individual.c

Prior to intradermal injection, cleanse administration site with 70% alcohol or other antiseptic and allow to dry.bc Usual injection site is volar (preferred) or dorsal surface of forearm, approximately 4 inches below elbow.bc121 Avoid hairy areas, areas with lesions, areas near veins, swollen or red areas,bc121 and areas without adequate subcutaneous tissue (e.g., concavities over tendon or bone).a

Potential for a drop of blood when needle withdrawn from injection site.c Remove any blood at injection site gently with gauze to avoid squeezing out tuberculin.c

Avoid recapping needle following use; properly dispose of used needles and syringes.c

Mantoux Method

With needle bevel pointing upward, insert needle into the most superficial layers of the skin and inject slowly.bc

A pale bleb about 6–10 mm in diameter should form at injection site.bc Bleb is absorbed within minutes; no dressing required.bc

If improperly administered (i.e., no bleb formed) or if dose leaks from injection site, repeat test immediately at another site at least 5 cm (2 inches) from original injection site; indicate site used for second test in patient’s record or by circling second site.bc121

Examine test site 48–72 hours after administration.bce121 (See Interpretation of Tuberculin Reaction under Dosage and Administration.)

Interpretation of Tuberculin Reaction

Only trained health professionals should interpret tuberculin skin test; interpretation by untrained individuals or family member not reliable.ce

At 48–72 hours after administration, visually inspect and palpate test site to determine extent of induration.bc121 Disregard finding of erythema (no diagnostic value); in absence of induration, an area of erythema with diameter >10 mm indicates too deep an injection and requires retesting.bc Note and record presence and extent of necrosis and edema, although these findings have no diagnostic value.bc

Measure diameter of palpable induration transversely to long axis of forearm.bce Record in mm (including 0) and interpret reaction using guidelines from manufacturer, ATS, and CDC.bc121 (See Table 1.)

Positive in individuals (including children ≥4 years of age) with no risk factors for TBbcei121144

<15 mm

Negative in normal, healthy individuals with no risk factors for TB (lack of hypersensitivity to tuberculin);bc TB highly unlikelyb

When of diagnostic importance, accept negative reaction as proof that sensitivity is absent only after normal reactivity to nonspecific irritants has been demonstrated.b In individuals suspected of being TB positive who exhibit negative reaction to tuberculin testing, perform second test to exclude possibility of active TB.c Individuals with negative reaction to initial and second test may be considered tuberculin negative.c

A positive reaction may indicate latent infection, prior infection, and/or M. tuberculosis disease and may not indicate active TB;cd individuals with a positive reaction should be considered positive by current public health guidelines and referred for further medical evaluation.cd

A negative tuberculin skin test should not be used to exclude active TB in individuals with symptoms compatible with TB (see False-negative Reactions under Cautions).be

Booster Effect and Two-Step Testing

If tuberculin sensitivity has waned (see Actions), initial testing will produce a small or negative reaction.bc121 Repeated testing may boost size of reaction (booster effect), which can be misinterpreted as a conversion (i.e., positive reaction indicative of recent infection with M. tuberculosis).bc121144

Therefore, individuals requiring routine periodic testing (e.g., health-care professionals, residents and workers in hospitals, nursing homes, mental institutions, prisons) should initially receive 2-step testing (i.e., a repeat tuberculin test after an initial negative reaction)i to permanently document infectivity status (e.g., uninfected, previously infected).bc121 If first test is negative, use result of second test performed 1–4 weeks later to determine TB status.121c If reaction to second test is positive, individual is considered previously infected; if reaction is negative, individual is considered uninfected.c121 In these uninfected individuals, a reaction size of ≥10 mm upon repeat testing within a 2-year period is considered a conversion.c121144

Individuals whose second test is negative, but whose reaction is positive after one year, are considered to have newly acquired TB infection and should be managed accordingly.c

Dosage

Each dose (0.1 mL) is bioequivalent to 5 US units (TU) of the US reference standard (PPD-S).bc

Warnings/Precautions

Warnings

Previous Severe Reaction

Risk of severe reaction at test site in individuals who previously experienced a severe reaction (e.g., vesiculation, ulceration, necrosis).b Use not recommended in such individuals.b (See Contraindications under Cautions.)

Reactivity to test possibly depressed or suppressed for 5–6 weeks following viral infections, immunization with certain live virus vaccines, or discontinuance of corticosteroid or immunosuppressive therapy.b (See Interactions.)

False-positive Reactions

Cannot reliably distinguish between reactions caused by BCG vaccination and those caused by natural mycobacterial infections.c144 In individuals with prior BCG vaccination, indurations ≥20 mm in diameter not likely caused by BCG vaccination.144

Test reaction of ≥10 mm probably attributable to M. tuberculosis infection in a BCG-vaccinated individual from a country with a high prevalence of TB or who is in close contact with another person with infectious TB (especially if contact has spread M. tuberculosis to others) or if individual continually exposed to groups with a high TB prevalence.c

Sensitivity gradually wanes with time (period of years) but may be boosted/prolonged by periodic tuberculin testing.bc144 (See Booster Effect and Two-Step Testing under Dosage and Administration.)

Strongly Positive Reactions

Some manufacturers recommend using cold packs or topical corticosteroid preparations for symptomatic relief of pain, pruritus, and discomfort at injection site.b However, topical 1% hydrocortisone ointment shown to be ineffective in reducing extent or rate of resolution of induration reaction.a

Specific Populations

Pregnancy

Pediatric Use

Due to an immature immune system, infants <6 weeks of age infected with M. tuberculosis may not react to test.b105 In older infants and children, tuberculin sensitivity develops 2–12 weeks (median: 3–6 weeks) after initial infection.ce

Very young children infected with M. tuberculosis at increased risk for active tuberculosis.c During contact investigations, give high priority to skin testing and treatment in young children and infants exposed to individuals with active TB.c

Geriatric Use

Skin test sensitivity may wane with advancing age;b skin test reaction may develop slowly and not be maximal until >72 hours.bc

Actions

Produces delayed hypersensitivity response (e.g., local vasodilation, edema, infiltration of leukocytes) in individuals with tuberculin sensitivity (e.g., those infected with M. tuberculosis or other mycobacteria, those with history of BCG vaccination).bc Test not specific for M. tuberculosis; other nontuberculous mycobacteria may cross-react.abc

Tuberculin sensitivity generally persists throughout life but may gradually diminish or disappear with time (over a period of years) or advancing age.bc121 Upon initial testing after sensitivity has waned, reactivity may be small or absent.bc121 (See Booster Effect and Two-Step Testing under Dosage and Administration.)

Advice to Patients

Risk of pain, pruritus, and discomfort at injection site.bc Importance of informing clinician if vesiculation, ulceration, or necrosis occurs.bc

Importance of patient returning to clinician 48–72 hours after skin test administration for interpretation of test.bc

117. Centers for Disease Control. Screening for tuberculosis and tuberculous infection in high-risk populations and the use of preventive therapy for tuberculous infection in the United States: recommendations of the Advisory Committee for the Elimination of Tuberculosis (ACET). MMWR Morb Mortal Wkly Rep. 1990; 39(Suppl RR-8):1-12. [PubMed 2294395]

134. Centers for Disease Control and Prevention. Essential components of a tuberculosis prevention and control program: recommendations of the Advisory Council for the Elimination of Tuberculosis. MMWR Morb Mortal Wkly Rep. 1995; 44(RR-11):1-16. [PubMed 7799912]

136. Centers for Disease Control and Prevention. The role of BCG vaccine in the prevention and control of tuberculosis in the United States: a joint statement by the Advisory Council for the Elimination of Tuberculosis and the Advisory Committee on Immunization Practices. MMWR Morb Mortal Wkly Rep. 1996; 45(No. RR-4):1-18. [PubMed 8531914]

f. Centers for Disease Control and Prevention. Controlling tuberculosis in the United States: recommendations from the American Thoracic Society, CDC, and the Infectious Diseases Society of America. MMWR Morb Mortal Wkly Rep. 2005; 54(RR-12): 1-81.

g. Centers for Disease Control and Prevention. Prevention and control of tuberculosis in correctional and detention facilities: recommendations from the CDC. MMWR Morb Mortal Wkly Rep 2006; 55: (RR-9) 1-54.

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